float angle = 0;

void setup() {
  size(200, 200);
  frameRate(30);
}

void draw() {
  background(#ffffff);
  
  translate(35, 35);
  rotate(angle);
  fill(#ff0000);
  stroke(#000000);
  rect(-25, -25, 50, 50);
  angle += 0.05;
}